Sometimes I have needed to rebase all programs. To do this,
do the command: rebase-trigger full
If you're not able to run bash to run this, you can run dash
from Windows CMD and give an explicit path, e.g.,
/cygdrive/c/cygwin/bin/rebase-trigger full
would do the right thin on my installation. But even that won't
help if you're running 32-bit and have installed too many packages.
There is only so much room in the address space for the various
possible DLLs that might be loaded.

Keith,
in addition to Elliot's comment, you can use
rebase -si
output to provide an overview of how many dll's are present
and in which address they are mapped.
$ rebase -si |sort -r --key=5 | head
will provide the list of the one absorbing more address space.

Except the octave-tisean patological case, that I recommend to not
install if you don't really need it, usually LLVM and ICU